SPED Materials Selection & Specification 2

Question 1

Which ASME material specification covers seamless and welded austenitic stainless steel pipe?

Accepted Answer

SA-312

Answer

SA-312 covers seamless, straight-seam welded, and heavily cold worked welded austenitic stainless steel pipe.

Question 2

What is the primary reason duplex stainless steel is selected over austenitic stainless steel in chloride-containing environments?

Accepted Answer

Superior resistance to stress corrosion cracking

Answer

Duplex stainless steels have a two-phase ferritic-austenitic microstructure that provides significantly better resistance to chloride stress corrosion cracking than standard austenitic grades.

Question 3

SA-333 Grade 6 pipe is specifically intended for service at:

Accepted Answer

Cryogenic and low-temperature service

Answer

SA-333 Grade 6 is a low-temperature carbon steel pipe specification with a minimum impact test temperature of −50°F.

Question 4

Which corrosion mechanism is most critical when selecting piping materials for a wet H₂S service application?

Accepted Answer

Sulfide stress cracking (SSC)

Answer

Wet H₂S environments produce atomic hydrogen that diffuses into steel and can cause sulfide stress cracking (SSC) in high-hardness or high-strength materials.

Question 5

According to ASME B31.3, the basic allowable stress for a piping material is primarily derived from:

Accepted Answer

The lesser of fractions of ultimate tensile strength and yield strength at temperature

Answer

ASME B31.3 sets allowable stress as the lesser of specific fractions of the tensile and yield strengths at design temperature, among other criteria.

(SPED) Society of Piping Engineers and Designers Certification Practice Test

(SPED) Society of Piping Engineers and Designers Certification Practice Test

SPED Materials Selection & Specification 2